Note: Descriptions are shown in the official language in which they were submitted.
A SNOW BIKE AND A FRONT SUSPENSION FOR A SNOW BIKE
BACKGROUND
[0001] The present disclosure relates to a snow bike and in particular to a
front
suspension for a snow bike.
[0002] Snow
bikes are known in the snowmobile art. These vehicles are usually
converted for winter use by converting a dirt bike into a snow bike, by
replacing the
front tire with a ski and the rear wheel with a rear suspension and track.
Such snow
bikes are known from our U.S. patents and patent applications, namely: U.S.
Patent
No. 8,910,738; and U.S. Patent Application Publication Nos. 2012/0222908;
2015/0144412; 2015/0259032; 2016/0280331; 2017/0129569; 2017/0129526 and
2017/0129570.
SUMMARY
[0003] In one
embodiment of the invention, a front fork assembly of a snow bike
comprises: a left leg having an upper leg portion and a lower leg portion, the
left leg
upper and lower leg portions being linearly movable relative to each other; a
right leg
having an upper leg portion and a lower leg portion, the right leg upper and
lower leg
portions being linearly movable relative to each other; a ski mount having a
lower
end for coupling to a ski and an upper end for coupling to the left and right
legs; and
a linear force element coupled to the left and right legs with a first end
adjacent first
ends of the left and right legs and a second end coupled to the ski, the
linear force
element having a different linear force characteristic than the left and right
legs,
wherein the upper leg portions of the left and right legs are coupled to each
other by
way of a triple clamp and the first end of the linear force element is coupled
to a
bottom of the triple clamp.
[0004] In
another embodiment, a front fork assembly for a snow bike comprises:
a left leg having an upper leg portion and a lower leg portion, the left leg
upper and
lower leg portions being linearly movable relative to each other; a right leg
having an
upper leg portion and a lower leg portion, the right leg upper and lower leg
portions
being linearly movable relative to each other; a ski mount having a lower end
for
coupling to a ski and an upper end for coupling to the left and right legs;
and a linear
force element coupled to the left and right legs with a first end adjacent
first ends of
1
CA 2995818 2019-07-16
[0005] the left and right legs and a second end for coupling to the ski,
wherein
the linear force element is an air shock, the linear force element providing
dampening to the right and left legs during the linear movement of the upper
and
lower leg portions of the left and right legs.
[0006] In yet another embodiment, a snow bike comprises: a frame; a
powertrain
supported by the frame; a rear suspension; a drive supported by the rear
suspension
and coupled to the powertrain; and a front suspension. The front suspension
comprises: a left leg having an upper leg portion and a lower leg portion, the
left leg
upper and lower leg portions being. linearly movable relative to each other; a
right leg
having an upper leg portion and a lower leg portion, the right leg upper and
lower leg
portions being linearly movable relative to each other; a ski mount having an
upper
end for coupling to the left and right legs; and a linear force element
coupled to the
left and right legs with an upper end adjacent upper ends of the left and
right legs
and a lower end coupled to the ski, the linear force element having a
different linear
force characteristic than the left and right leg. The snow bike further
comprises a
front ski coupled to the front suspension.
2
CA 2995818 2019-07-16
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The embodiments will now be described by way of reference to the
drawing figures, where:
[0008] FIG. 1 is a left side view of the snow bike and front suspension of
the
present disclosure;
[0009] FIG. 2 is a front left perspective view of the front suspension
shown in FIG.
1;
[0010] FIG. 3 is a left rear view .of the front suspension shown in FIG. 2;
[0011] FIG. 4 is a left side view of the suspension of FIG. 2;
[0012] FIG. 5 is a perspective view similar to that of FIG. 3 showing the
suspension in an exploded manner;
[0013] FIG. 5A is an enlarged view of the spindle portion of the ski mount
shown
in FIG. 5;
[0014] FIG. 6 is a cross-sectional view taken through lines 6-6 of FIG. 2;
[0015] FIG. 7 is a cross-sectional view taken through lines 7-7 of FIG. 2;
[0016] FIG. 8 is a cross-sectional view taken through lines 8-8 of FIG. 2;
[0017] FIG. 9 is a view similar to that of FIG. 2 showing the suspension in
a fully
compressed configuration;
[0018] FIG. 10 is a view similar to that of FIG. 3 shown in a fully
compressed
condition;
[0019] FIG. 11 is a view similar to that of FIG. 4 shown in suspension in a
fully
compressed condition; and
[0020] FIG. 12 is a view similar to that of FIG. 3 showing an alternate
lower shock
mounting.
3
CA 2995818 2019-07-16
DETAILED DESCRIPTION
[0021] With reference first to FIG. 1, a snow bike is shown generally at 2.
Snow
bike 2 includes a dirt bike 4 having the front and rear wheels removed. Snow
bike 2
includes a frame 6, a powertrain 8,.a seat 10, steering assembly 12 including
handlebars 14, and a front suspension 15. Front suspension is in part defined
by the
existing front fork assembly having forks 18, designated as left front fork
18L and
right front fork 18R. A front fender 20 is positioned between the front forks
18. As
shown, front wheel is removed and replaced with a front ski mount 28 which
couple
to the forks 18 as discussed herein. The rear wheel is removed and includes a
rear
suspension 30, including a tunnel 32 and a track 34. Rear suspension 30 could
be
similar to any of the rear suspensions shown in our U.S. patents and patent
applications, namely: U.S. Patent No. 8,910,738; and U.S. Patent Application
Publication Nos. 2012/0222908; 2015/0144412; 2015/0259032; 2016/0280331;
2017/0129569; 2017/0129526 and 2017/0129570.
[0022] With reference now to FIGS. 2-4, front suspension 15 is shown
comprising
the forks or legs 18L and 18R which are coupled to ski mount 28, which in turn
is
coupled to front ski 40. It should be understood that left leg 18L and right
leg 18R
are coupled to the frame 6 of the snow bike by way of a triple clamp 42 having
a
lower left clamp portion 44L and a lower right hand clamp portion 44R; and an
upper
left clamp portion 46L and an upper right clamp portion 46R. These clamp
portions
clamp to associated legs 18L and 18R as is known in the art. Triple clamp 42
also
includes a center pin 48 which may couple to a down tube (not shown) of the
3a
CA 2995818 2019-07-16
. .
frame 6, such that legs 18L and 18R may rotate about pin 48 for steering. As
shown
in FIGS. 2-4, lower ends of the legs 18L and 18R are coupled to the ski mount
28 in
order to turn the ski 40 for purposes of steering. As also shown, front
suspension 15
further includes a linear force element 49 which is coupled between a bottom
of triple
clamp 42 and a top of the ski mount 28, as further described herein.
[0022] With reference now to FIGS. 5-8, the ski mount 28 will be described
in
greater detail. With reference first to FIG. 5A, ski mount 28 includes a
spindle 50
having spaced apart plate portions 52. The plate portions 52 are spaced apart
by
way of a box-shaped inner plate 54 and a pin 56. A bracket 60 has a base
portion
62 coupled between plates 52 and includes a clevis 64 having apertures at 66.
Upper ends of plates 52 include apertures at 70 and lower ends of plate 52
include
apertures 72.
[0023] As shown in FIG. 5, brackets 76 are coupled to a top of the plates
52 by
way of fasteners 78 extending through apertures 80 of bracket 76 and into
threaded
engagement with threaded apertures 70 (FIG. 5A). Brackets 76 retain clamps 86
by
way of fasteners 88 and 90 which couple to ends of legs 18L and 18R as best
shown
in FIG. 2. Brackets 76 could be integrated with plate portions 52 which would
extend
from an upper edge of the plate portions 52.
[0024] A lower coupler 100 is coupled to apertures 72 (FIG. 5A) by way of
fasteners 102, 104 and 106. Fasteners 102 extend through apertures 110 of
coupler
100. Coupler 100 is also coupled to ski 40 and in particular, to a mount
portion 120
of ski 40 where ski mount 120 includes up standing walls 122 having apertures
124.
Coupler 100 includes an aperture at 130 which receives a sleeve 132 which
thereupon receives bushings 134, thereover. As shown best in FIG. 8, bushings
134
overlap sleeve 132 and sleeves 138 extend into aperture 124 (FIG. 5 of ski
mount
120). Spacers 136 extend between heads of the bushings 134, 138. Fastener 140
is
received through washer 142 through aperture 124 and through a combination of
bushings 138, 136, 134 and sleeve 130 to receive fasteners 150 and 152.
Fasteners
140, 150 and 152 couple the ski 40 to the coupler 100. A rubber mount 160 is
positioned in the ski mount 120 and conforms to, but allows movement between,
coupler 100 and ski 40 as best shown in FIG. 6.
CA 2995818 2018-02-21 4
[0025] Finally, as shown in FIG. 5, suspension 15 includes bracket 170
having a
clevis 172. Bracket 170 is mounted to a bottom of the triple clamp 42 through
apertures 174. As shown best in FIG. 7, bracket 170 traps fender 20 between
triple
clamp 42 and bracket 170. Thus, as shown in FIG. 5, linear force element 49 is
coupled to the snow bike 2 by way of fastener 176 extending through aperture
180 of
linear force element 49 and through clevis 172; and by way of fastener 182
extending through aperture 178 of linear force element 49 and through clevis
64
(FIG. 5A). Thus, linear force element 49 supplements the existing shocks in
the front
legs 18L and 18R.
[0026] With reference now to FIGS. 9-11, the operation of the front
suspension 15 will now be described in greater detail. As shown, suspension 15
is
shown in the fully collapsed state where both the shock absorbers of the front
forks
18L, 18R and linear force element 49 are shown in a fully compressed state. As
shown, linear force element 49 is an air shock available from Fox Shox and has
the
same linear travel as the motor bike forks 18L, 18R; a range of 8 to 14",
preferably
to 12". In the embodiment shown the linear travel is 11". In the embodiment
shown, linear force element 49 is an EVOL Series Float shock available from
Fox
Shox located at 915 Disc Dr., Scotts Valley, CA 95066. This shock is an air
shock
with a progressive rate which progressive range is adjustable.
[0027] While the LFE 49 is shown herein as an air shock, other linear force
elements are possible. For example, the linear force element could be a gas
shock
or a shock with a spring over, similar to that described in our US Patent
8,079,602.
The linear force element could also be a hydraulic shock, or a spring or a
series of
springs. These components could have a linear or progressive rate which rate
is
adjustable. In addition, linear force element could be a linkage coupled
between the
triple clamp and the ski, a linkage similar to that described in our US Patent
as the
coupled suspension system. In that way, the stroke of the shock could be tuned
to
vary from the stroke of the front forks 18L and 18R.
[0028] Linear force element 49 works in combination with the motor bike
shocks
within forks 18L, 18R to give the front forks the proper spring rate and
damping force
for the snow bike. In the embodiment shown, linear force element 49 is also in
compression the entire time; that is between the positions shown in 2-4 and 9-
11.
CA 2995818 2018-02-21 5
[0029] It should be appreciated that the spindle 50 could be comprised of
an
integrated unit where the all of the components are fixed to each other,
namely
spindle 50, brackets 76, the inner portions of brackets 86 and coupler 100.
This
could be assembled by such means as welding or adhesives for example. The
integrated spindle could also be a forging or casting which is in a homogenous
state.
[0030] It should also be appreciated that a lower end of the LFE 49 could
be
attached to a modified coupler 100. As shown in FIG. 12, a coupler 200 is
shown at
200, which is identical to coupler 100, yet it includes a notch at 202 to
receive a
lower end of LFE 49. In this manner, fastener 102 couples both the coupler 200
and
the LFE 49, as fastener 102 extends through aperture 178 (FIG. 5) of LFE 49.
[0031] In the above described embodiment, the ski mounts 28 and linear
force
element 49 are designed as a kit for converting a motorbike to a snow bike
having
existing shocks positioned in the front forks, or for retrofitting existing
snow bikes. In
the case where a new snow bike front suspension is desired, the front
suspension
could include front forks 18L and 18R, but in this case, the front forks would
not
include internal shocks, but rather would only be struts which allow linear
telescopic
movement but would not have any internal dampening resistance. While this
design
would include a linear force element 49, the spring rate of the combined
suspension
15 would still be consistent with that disclosed above.
[0032] While this invention has been described as having an exemplary
design,
the present invention may be further modified within the spirit and scope of
this
disclosure. This application is therefore intended to cover any variations,
uses, or
adaptations of the invention using its general principles. Further, this
application is
intended to cover such departures from the present disclosure as come within
known
or customary practice in the art to which this invention pertains.
CA 2995818 2018-02-21 6
